The present invention relates to an IC card and, more particularly, to an IC card radiating heat which mounted elements such as semiconductor elements generate when put into operation.
FIG 6 is a sectional view showing a structure of a known IC card. In FIG. 6, an IC card 1 comprises three side walls as a main frame 5 of molded resin, a top and bottom made of conductive panels 2a and 2b and attached to the main frame 5 from above and below, and a connector 8 having a terminal 7 for transferring signals to or from an external unit and formed on the other side wall. A substrate 3 is, as illustrated, mounted in the IC card 1. One end of the terminal 7 is attached to the substrate 3. A conducting means 6 such as a spring is disposed in the IC card 1 so that the conducting means 6 electrically connects the two conductive panels 2a and 2b the top and bottom of the IC card 1. On the substrate 3, as illustrated, elements 4 including semiconductor elements 4a and wiring patterns (not shown) are mounted. The mounted elements 4 and terminal 7 are electrically connected to one another through the wiring patterns.
In the known IC card, as mentioned above, the semiconductor elements 4a on the substrate 3 may produce a considerable quantity of heat when put into operation, and malfunction eventually. It is therefore required generated by the semiconductor elements 4a . In the known IC card, as shown in FIG. 6, the heat generated by the semiconductor elements 4a is transmitted from the packing of the semiconductor elements 4a to the conductive panels 2a and 2b through the air inside the IC card, and then radiated outside through the conductive panels 2a and 2b. Otherwise, the heat is transmitted to the substrate 3 through leads 4aa attached to the semiconductor elements 4a, transferred from the substrate 3 to the air within the IC card, and then radiated outside through the conductive panels 2a and 2b. Thus, heat is radiated via the air inside an IC card. This causes the temperature inside the IC card to considerably, resulting in inefficient heat radiation.
A structure designed to cope with this requirement of heat radiation is disclosed in, Japanese Patent Laid-Open No.3-182397 wherein a space between the semiconductor elements 4a and casing conductive panel 2a is filled with an adhesive made of a material of high heat conductivity. However, in the IC card having the above structure disclosed in Japanese Patent Laid-Open No. 3-82397, since the IC card is usually inserted into a host device such as a reader/writer during operation, the heat generated by the host device may be transmitted inversely to the semiconductor elements 4a mounted in the IC card through the casing conductive panel 2a and the adhesive filled between the semiconductor elements 4a and the casing conductive panel 2a. Therefore, the heat generated from the semiconductor elements 4a mounted in the IC card cannot be radiated efficiently.